Sarcoptes scabiei var. suis: Mange mite; itch mite.

General Description: Sarcoptes is a tiny, greyish-white mite 0.3 to 0.5 mm. Long, with a round body, blunt mouthparts adapted for puncturing skin, and 8 stumpy legs.

Life Cycle: Female adult mites burrow tunnels in skin and lay eggs, beginning a cycle of incomplete metamorphosis. Larvae hatch out in 3 to 5 days and burrow side tunnels, or travel to the skin surface and make new tunnels or simple pockets in the outer layers of skin. Nymphs moult twice, and adult mites are produced about 17 days after eggs are laid. Mating may then occur, and egg laying commences 4 to 5 days later. All stages of sarcoptic mites are very susceptible to drying and can survive only for a few days off swine.

Location: Sarcoptes usually burrows in the skin of the head, ears, shoulders, and neck. In heavy infestations, the skin damage may spread all over the body.

Geographical Distribution: Sarcoptes is found wherever pigs are raised.

Significance: The mange mite is very important economically, because the annoyance it causes distracts swine from feeding, resulting in slower weight gain.

Effect on Host: The feeding and burrowing of Sarcoptes mites causes great irritation and itching and produces lesions with exudates that dry to crusts. Continued skin inflammation is accompanied by proliferation of subcutaneous connective tissue. The tender, thickened skin may crack, leaving deep wounds which are susceptible to bacterial infection. Infested swine are restless and continually scratch and rub. The inside of the ears will become inflamed and scabby.

Diagnostic Information: The mite is identified from deep skin scrapings which can be observed directly under the microscope or after digestion and concentration of the sample. A Rubbing Index (RI) has been developed to correlate the frequency of rubbing with the degree of infestation. The number of rubbing episodes observed in a 15 minute period is divided by the number of pigs observed generates the RI value. A RI of greater than 0.4 indicates a need to review mange control. It's important to differentiate from hyperkeratosis.

Control: Spraying has been the usual treatment for mange mites. Infested sows should be treated before farrowing to prevent transmission to the young pigs. The avermectins have been shown to be highly effective against sarcoptic mange mites.

Sarcoptic mites		Pig exhibiting particularly severe mange infestation on ears
Scanning electron microscope photo – sarcoptic mite		Mite eggs deposited in burrows in skin